The study examined modified Fenton (FeGAC/H2O2) pretreatment of the antibiotics amoxicillin and cloxacillin in aqueous solution for biological treatment. The treatment was optimized by the response surface methodology (RSM). The optimum operating conditions at pH3 were H2O2/COD molar ratio 2.0, FeGAC dose 3.5 g/L and reaction time 90 min for 87.53% removal of COD, 78.01% removal of TOC, and 98.24% removal of NH3-N. Biodegradability (BOD5/COD ratio) improved from zero to 0.36, indicating the effluent was amenable to biological treatment. Meanwhile, FTIR spectra indicated degradation of the antibiotics. Compared with Fenton or photo-Fenton, modified Fenton (FeGAC/H2O2) was more effective in the pre-treatment of the antibiotics amoxicillin and cloxacillin in aqueous solution for biological treatment.
Leachate pollution is one of the main problems in landfilling. Researchers have yet to find an effective solution to this problem. The technology that can be used may differ based on the type of leachate produced. Coliform bacteria were recently reported as one of the most problematic pollutants in semi-aerobic (stabilized) leachate. In the present study, the performance of the Electro-Fenton process in removing coliform from leachate was investigated. The study focused on two types of leachate: Palau Borung landfill leachate with low Coliform content (200 MPN/100 m/L) and Ampang Jajar landfill leachate with high coliform content (>24 × 10(4)MPN/100 m/L). Optimal conditions for the Electro-Fenton treatment process were applied on both types of leachate. Then, the coliform was examined before and after treatment using the Most Probable Number (MPN) technique. Accordingly, 100% removal of coliform was obtained at low initial coliform content, whereas 99.9% removal was obtained at high initial coliform content. The study revealed that Electro-Fenton is an efficient process in removing high concentrations of pathogenic microorganisms from stabilized leachate.
A novel optical detection system consisting of combination of uricase/HRP-CdS quantum dots (QDs) for the determination of uric acid in urine sample is described. The QDs was used as an indicator to reveal fluorescence property of the system resulting from enzymatic reaction of uricase and HRP (horseradish peroxidase), which is involved in oxidizing uric acid to allaintoin and hydrogen peroxide. The hydrogen peroxide produced was able to quench the QDs fluorescence, which was proportional to uric acid concentration. The system demonstrated sufficient activity of uricase and HRP at a ratio of 5U:5U and pH 7.0. The linearity of the system toward uric acid was in the concentration range of 125-1000 µM with detection limit of 125 µM.
There are reports of improved metabolic outcomes due to consumption of germinated brown rice (GBR). Many of the functional effects of GBR can be linked to its high amounts of antioxidants. Interestingly, dietary components with high antioxidants have shown promise in the prevention of neurodegenerative diseases like Alzheimer's disease (AD). This effect of dietary components is mostly based on their ability to prevent apoptosis, which is believed to link oxidative damage to pathological changes in AD. In view of the rich antioxidant content of GBR, we studied its potential to modulate processes leading up to AD.
The pathogenesis of Alzheimer's disease involves complex etiological factors, of which the deposition of beta-amyloid (Aβ) protein and oxidative stress have been strongly implicated. We explored the effects of H2O2, which is a precursor for highly reactive hydroxyl radicals, on neurotoxicity and genes related to AD on neuronal cells. Candidate bioactive compounds responsible for the effects were quantified using HPLC-DAD. Additionally, the effects of germinated brown rice (GBR) on the morphology of Aβ(1-42) were assessed by Transmission Electron Microscopy and its regulatory effects on gene expressions were explored. The results showed that GBR extract had several phenolic compounds and γ-oryzanol and altered the structure of Aβ(1-42) suggesting an antiamyloidogenic effect. GBR was also able to attenuate the oxidative effects of H2O2 as implied by reduced LDH release and intracellular ROS generation. Furthermore, gene expression analyses showed that the neuroprotective effects of GBR were partly mediated through transcriptional regulation of multiple genes including Presenilins, APP, BACE1, BACE2, ADAM10, Neprilysin, and LRP1. Our findings showed that GBR exhibited neuroprotective properties via transcriptional regulation of APP metabolism with potential impact on Aβ aggregation. These findings can have important implications for the management of neurodegenerative diseases like AD and are worth exploring further.
Palm kernel cake (PKC) is the solid residue following oil extraction of palm kernels and useful to fatten animals either as a single feed with only minerals and vitamins supplementation, or mixed with other feedstuffs such as corn kernels or soy beans. The occurrence of mycotoxins (aflatoxins, ochratoxins, zearalenone, and fumonisins) in feed samples affects the animal's health and also serves as a secondary contamination to humans via consumption of eggs, milk and meats. Of these, aflatoxin B₁ (AFB₁) is the most toxically potent and a confirmed carcinogen to both humans and animals. Methods such as High Performance Liquid Chromatography (HPLC) and Liquid Chromatography-Mass Spectrometry (LC-MS/MS) are common in the determination of mycotoxins. However, these methods usually require sample pre-treatment, extensive cleanup and skilled operator. Therefore, in the present work, a rapid method of electrochemical immunosensor for the detection of AFB₁ was developed based on an indirect competitive enzyme-linked immunosorbent assay (ELISA). Multi-walled carbon nanotubes (MWCNT) and chitosan (CS) were used as the electrode modifier for signal enhancement.N-ethyl-N'-(3-dimethylaminopropyl)-carbodiimide (EDC) andN-hydroxysuccinimide (NHS) activated the carboxyl groups at the surface of nanocomposite for the attachment of AFB₁-BSA antigen by covalent bonding. An indirect competitive reaction occurred between AFB₁-BSA and free AFB₁ for the binding site of a fixed amount of anti-AFB₁ antibody. A catalytic signal based on horseradish peroxidase (HRP) in the presence of hydrogen peroxide (H₂O₂) and 3,3',5,5'-tetramethylbenzidine (TMB) mediator was observed as a result of attachment of the secondary antibody to the immunoassay system. As a result, the reduction peak of TMB(Ox)was measured by using differential pulse voltammetry (DPV) analysis. Based on the results, the electrochemical surface area was increased from 0.396 cm² to 1.298 cm² due to the electrode modification with MWCNT/CS. At the optimal conditions, the working range of the electrochemical immunosensor was from 0.0001 to 10 ng/mL with limit of detection of 0.1 pg/mL. Good recoveries were obtained for the detection of spiked feed samples (PKC, corn kernels, soy beans). The developed method could be used for the screening of AFB₁ in real samples.
We have determined the protective effects of Thymus serpyllum (TS) extract and nanoparticle-loaded TS on hydrogen peroxide-induced cell death of mesenchymal stromal cells (MSCs) in vitro. Gas chromatography-mass spectroscopy confirmed the spectrum of active components in the extract. Out of the three different extracts, the hexane extract showed significant free radical scavenging activity. Treatment of MSCs with H2O2 (hydrogen peroxide) significantly increased intracellular cell death; however, pretreatment with TS extract and nanoparticle-loaded TS (200 μg/ml) suppressed H2O2-induced elevation of Cyt-c and MMP13 and increased the survival rates of MSCs. H2O2-induced (0.1 mM) changes in cytokines were attenuated in the extract and nanoparticles by pretreatment and cotreatment at two time points (p < 0.05). H2O2 increased cell apoptosis. In contrast, treatment with nanoparticle-loaded TS suppressed the percentage of apoptosis considerably (p < 0.05). Therefore, TS may be considered as a potential candidate for enhancing the effectiveness of MSC transplantation in cell therapy.
Pleurotus giganteus (Berk. Karunarathna and K.D. Hyde), has been used as a culinary mushroom and is known to have medicinal properties but its potential as an anti-inflammatory agent to mitigate inflammation triggered diseases is untapped. In this study, the molecular mechanism underlying the protective effect of ethanol extract of P. giganteus (EPG) against lipopolysaccharide (LPS) and combination of LPS and hydrogen peroxide (H2O2)-induced inflammation on RAW 264.7 macrophages was investigated.
Endothelial cell injury caused by reactive oxygen species (ROS) plays a critical role in the pathogenesis of cardiovascular diseases. Omentin, an adipocytokine that is abundantly expressed in visceral fat tissue, has been reported to possess anti-inflammatory and antidiabetic properties. However, endothelial protective effects of omentin against oxidative stress remain unclear. This study aimed to evaluate the protective effect of omentin against hydrogen peroxide (H2O2)-induced cell injury in human umbilical vein endothelial cells (HUVECs). Cytotoxicity and cytoprotective effects of omentin were evaluated using 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The apoptotic activity of HUVECs was detected using Annexin-V/PI and Hoechst 33258 staining methods. Antioxidant activity of omentin was evaluated by measuring both reactive oxygen species (ROS) levels and glutathione peroxidase (GPx) activity. No cytotoxicity effect was observed in HUVECs treated with omentin alone at concentrations of 150 to 450 ng/ml. MTT assay showed that omentin significantly prevented the cell death induced by H2O2 (p < 0.001). Hoechst staining and flow cytometry also revealed that omentin markedly prevented H2O2-induced apoptosis. Moreover, omentin not only significantly inhibited ROS production (p < 0.01) but also significantly (p < 0.01) increased GPx activity in HUVECs. In conclusion, our data suggest that omentin may protect HUVECs from injury induced by H2O2.
This study aimed to isolate a potent antiglucosidase and antioxidant fraction from Stenochlaena palustris. Extraction was performed with hexane, chloroform, ethyl acetate, methanol, and water. Antiglucosidase, 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging and ferric reducing antioxidant power (FRAP) assays found methanol extract (ME) to be the most active. Water fraction (WF) of ME was a stronger α-glucosidase inhibitor (EC50 2.9 μg/mL) than quercetin, with weak antiamylase activity. WF was a competitive α-glucosidase inhibitor. DPPH scavenging activity of WF (EC50 7.7 μg/mL) was weaker than quercetin. WF (EC50 364 μg/mL) was a stronger hydrogen peroxide scavenger than gallic acid (EC50 838 μg/mL) and was equally strong as quercetin in scavenging superoxide. WF possessed moderate copper chelating activity. WF was enriched in total phenolics (TP) and hydroxycinnamic acids (THC). TP correlated with antioxidant activity (R(2) > 0.76). Only THC correlated with antiglucosidase activity (R(2) = 0.86). Overall, WF demonstrated concurrent, potent antiglucosidase and antioxidant activities.
This study was aimed to isolate and evaluate neuroprotective compounds from the hexane extract of the bark of Mesua kunstleri (Clusiaceae) on H(2)O(2)-induced apoptosis in NG108-15 cells. Five 4-phenylcoumarins were isolated by using various chromatographic techniques via neuroprotective activity-guided fractionation and isolation from the active hexane extract. The chemical structures of the isolated compounds were confirmed by NMR spectroscopic data interpretation and comparison with literature values. Cell viability data demonstrated that mesuagenin C 3 significantly increased cell viability. Hoechst 33342/PI staining illustrated mesuagenin C 3 was able to abate the nuclear shrinkage, chromatin condensation and formation of apoptotic bodies. Pretreatment with mesuagenin C 3 reduced total annexin V positive cells and increased the level of intracellular glutathione (GSH). Mesuagenin C 3 attenuated membrane potential (Δψm), reduced Bax/Bcl-2 ratio and inactivated of caspase-3/7 and -9. These results indicated that mesuagenin C 3 could protect NG108-15 cells against H(2)O(2)-induced apoptosis by increasing intracellular GSH level, aggrandizing Δψm, and modulating apoptotic signalling pathway through Bcl-2 family and caspase-3/7 and -9. These findings confirmed the involvement of intrinsic apoptotic pathway in H(2)O(2)-induced apoptosis and suggested that mesuagenin C 3 may have potential therapeutic properties for neurodegenerative diseases.
Goniothalamin (GN), a styryl-lactone isolated from Goniothalamus andersonii, has been demonstrated to possess antirestenostic properties by inducing apoptosis on coronary artery smooth muscle cells (CASMCs). In this study, the molecular mechanisms of GN-induced CASMCs apoptosis were further elucidated. Apoptosis assessment based on the externalization of phosphatidylserine demonstrated that GN induces CASMCs apoptosis in a concentration-dependent manner. The GN-induced DNA damage occurred with concomitant elevation of p53 as early as 2 h, demonstrating an upstream signal for apoptosis. However, the p53 elevation in GN-treated CASMCs was independent of NAD(P)H: quinone oxidoreductase 1 and Mdm-2 expression. An increase in hydrogen peroxide and reduction in free thiols confirmed the role for oxidative stress in GN treatment. Pretreatment with the pan-caspase inhibitor benzyloxycarbonyl-Val-Ala-Asp-fluoromethyl ketone (z-VAD-FMK) that significantly abrogated GN-induced CASMCs apoptosis suggested the involvement of caspase(s). The role of apical caspase-2, -8, and -9 was then investigated, and sequential activation of caspase-2 and -9 but not caspase-8 leading to downstream caspase-3 cleavage was observed in GN-treated CASMCs. Reduction of ATP level and decrease in oxygen consumption further confirmed the role of mitochondria in GN-induced apoptosis in CASMCs. The mitochondrial release of cytochrome c was seen without mitochondrial membrane potential loss and was independent of cardiolipin. These data provide insight into the mechanisms of GN-induced apoptosis, which may have important implications in the development of drug-eluting stents.
Numerous studies have revealed the presence of oxidative stress in parasitic infections. However, such studies were lacking in the Malaysian population. Previously, we have provided evidence that oxidative stress is elevated in Malaysians infected with intestinal parasites. Stool examinations revealed that about 47.5% of them were infected with the polymorphic protozoa, Blastocystis hominis. However, they were found to have mixed infection with other intestinal parasites.
Oxidative stress has been implicated as an important pathogenic factor in the pathophysiology of various life-threatening diseases such as cancer, cardiovascular diseases and diabetes. It occurs when the production of free radicals (generated during aerobic metabolism, inflammation, and infections) overcome the antioxidant defences in the body. Although previous studies have implied that oxidative stress is present in serum of patients with parasitic infection there have been no studies confirming oxidative stress levels in the Malaysian population infected with intestinal parasites. Three biochemical assays namely hydrogen peroxide (H2O2), lipid peroxidation (LP) and advanced oxidative protein product (AOPP) assays were carried out to measure oxidative stress levels in the urine of human subjects whose stools were infected with parasites such as Blastocystis hominis, Ascaris, Trichuris, hookworm and microsporidia. The levels of H2O2, AOPP and LP were significantly higher (P<0.001, P<0.05 and P<0.05 respectively) in the parasite-infected subjects (n=75) compared to the controls (n=95). In conclusion, the study provides evidence that oxidative stress is elevated in humans infected by intestinal parasites. This study may influence future researchers to consider free radical-related pathways to be a target in the interventions of new drugs against parasitic infection and related diseases.
PURPOSE: This study aimed to use non-invasive methods to assess and compare the levels of oxidative indices and non-enzymatic antioxidants in breast and colorectal cancer (CRC) patients. Various studies have reported on lipid peroxidation, hydrogen peroxide (H(2)O(2)) and ferric-reducing antioxidant power (FRAP) levels in the serum of cancer patients but this is the first report that highlights the significance of urinary-advanced oxidative protein product (AOPP) in cancer patients.
METHODS: The levels of advanced oxidative protein product (AOPP), hydrogen peroxide (H(2)O(2)), malondialdehyde (MDA) which is a marker for lipid peroxidation and ferric-reducing antioxidant power (FRAP) were measured in urine samples of breast (n = 101) and colorectal cancer (n = 49) patients attending the Oncology Clinic, University Malaya Medical Centre, Kuala Lumpur and were compared with 95 age-matched healthy individuals.
RESULTS: AOPP, H(2)O(2) and MDA levels in the urine were significantly higher in the CRC patients compared to the control subjects and breast cancer patients. In breast cancer patients, only AOPP level was elevated. FRAP level did not differ between breast and colorectal cancer patients but the levels were significantly lower compared to control subjects.
CONCLUSION: Urinary oxidative indices such as AOPP, H(2)O(2), and MDA as well as FRAP could serve as useful non-invasive oxidative stress markers in colorectal cancer but only AOPP serves as a useful urinary oxidative biomarker in breast cancer.
Study site: Oncology clinic, University Malaya Medical Centre (UMMC), Kuala Lumpur, Malaysia
Erythrocytes require glucose-6-phosphate dehydrogenase (G6PD) to generate NADPH and protect themselves against hemolytic anemia induced by oxidative stress. Peroxiredoxin 2 (Prx2) is a major antioxidant enzyme that requires NADPH to recycle its oxidized (disulfide-bonded) form. Our aims were to determine whether Prx2 is more highly oxidized in G6PD-deficient erythrocytes and whether these cells are able to recycle oxidized Prx2 after oxidant challenge. Blood was obtained from 61 Malaysian neonates with G6PD deficiency (average 33% normal activity) and 86 controls. Prx2 redox state was analyzed by Western blotting under nonreducing conditions. Prx2 in freshly isolated blood was predominantly reduced in both groups, but the median level of oxidation was significantly higher (8 vs 3%) and the range greater for the G6PD-deficient population. When treated with reagent H2O2, the G6PD-deficient erythrocytes were severely compromised in their ability to recycle oxidized Prx2, with only 27 or 4% reduction after 1 h treatment with 0.1 or 1 mM H2O2 respectively, compared with >97% reduction in control erythrocytes. The accumulation of oxidized Prx2 in oxidatively stressed erythrocytes with common G6PD variants suggests that impaired antioxidant activity of Prx2 could contribute to the hemolysis and other complications associated with the condition.-Cheah, F.-C., Peskin, A. V., Wong, F.-L., Ithnin, A., Othman, A., Winterbourn, C. C. Increased basal oxidation of peroxiredoxin 2 and limited peroxiredoxin recycling in glucose-6-phosphate dehydrogenase deficient erythrocytes from newborn infants.
Graphene (Gr)/gold (Au) and graphene-oxide (GO)/Au nanocomposites (NCPs) were synthesized by performing pulsed-laser-induced photolysis (PLIP) on hydrogen peroxide and chloroauric acid (HAuCl4) that coexisted with Gr or GO in an aqueous solution. A 3-month-long aqueous solution stability was observed in the NCPs synthesized without using surfactants and additional processing. The synthesized NCPs were characterized using absorption spectroscopy, transmission electron microscopy, Raman spectroscopy, energy dispersive spectroscopy, and X-ray diffraction to prove the existence of hybrid Gr/Au or GO/Au NCPs. The synthesized NCPs were further evaluated using the photocatalytic reaction of methylene blue (MB), a synthetic dye, under UV radiation, visible light (central wavelength of 470 nm), and full spectrum of solar light. Both Gr/Au and GO/Au NCPs exhibited photocatalytic degradation of MB under solar light illumination with removal efficiencies of 92.1% and 94.5%, respectively.
Biochar is a carbon-neutral solid fuel and has emerged as a potential candidate to replace coal. Meanwhile, spent coffee grounds (SCGs) are an abundant and promising biomass waste that could be used for biochar production. This study develops a biochar valorization strategy by mixing SCGs with hydrogen peroxide (H2O2) at a weight ratio of 1:0.75 to upgrade SCG biochar. In this dual pretreatment method, the H2O2 oxidative ability at a pretreatment temperature of 105 °C contributes to an increase in the higher heating value (HHV) and carbon content of the SCG biochars. The HHV and carbon content of biochar increase by about 6.5% and 7.8%, respectively, when compared to the unpretreated one under the same conditions. Maximized biochar's HHV derived via the Taguchi method is 30.33 MJkg-1, a 46.9% increase compared to the raw SCG, and a 6.5% increase compared to the unpretreated SCG biochar. The H2O2 concentration is 18% for the maximized HHV. A quantitative identification index of intensity of difference (IOD) is adopted to evaluate the contributive level of H2O2 pretreatment in terms of the HHV and carbon content. IOD increases with increasing H2O2 pretreatment temperature. Before torrefaction, SCGs' IOD pretreated at 50 °C is 1.94%, while that pretreated at 105 °C is 8.06%. This is because, before torrefaction, H2O2 pretreatment sufficiently weakens SCGs' molecular structure, resulting in a higher IOD value. The IOD value of torrefied SCGs (TSCG) pretreated at 105 °C is 10.71%, accounting for a 4.59% increase compared to that pretreated at 50 °C. This implies that TSCG pretreated by H2O2 at 105 °C has better thermal stability. For every 1% increase in IOD of TSCG, the carbon content of the biochar increases 0.726%, and the HHV increases 0.529%. Overall, it is demonstrated that H2O2 is a green and promising pretreatment additive for upgrading SCG biochar's calorific value, and torrefied SCGs can be used as a potential solid fuel to approach carbon neutrality.
In the present study, we attempted revalorization of pear (Pyrus pyrifolia L.) peel residue into high value-added nanomaterials. A green and facile one-pot isolation procedure was designed to simplify the isolation process of nanocellulose directly from pear peel residue. The one-pot approach employed in this work is interesting as the reaction involved less harmful chemicals usage and non-multiple steps. The reaction was carried out by adding hydrogen peroxide as an oxidant and chromium (III) nitrate as catalyst in the acidic medium under mild process conditions. FTIR spectroscopy proved that the pear peel derived nanocellulose was purely cellulose phases without the presence of non-cellulosic layer. XRD study indicated that the isolated nanocellulose possessed of cellulose I polymorph with high crystallinity index of 85.7%. FESEM analysis clearly revealed that the considerable size reduction during one-pot process. Remarkably, TEM analysis revealed that the isolated nanocellulose consisted of network-liked nature and spherical shaped morphologies with high aspect ratio of 24.6. TGA showed nanocellulose has lower thermal stability compared to pear peel residue. This study provided a cost-effective method and straightforward one-pot process for fabrication of nanocellulose from pear peel residue. This is the first investigation on the nanocellulose extraction from pear fruit.
This paper presents a comparative study of the characteristic of unfoamed and foamed geopolymers after exposure to elevated temperatures (200-800 °C). Unfoamed geopolymers were produced with Class F fly ash and sodium hydroxide and liquid sodium silicate. Porous geopolymers were prepared by foaming with hydrogen peroxide. Unfoamed geopolymers possessed excellent strength of 44.2 MPa and degraded 34% to 15 MPa in foamed geopolymers. The strength of unfoamed geopolymers decreased to 5 MPa with increasing temperature up to 800 °C. Foamed geopolymers behaved differently whereby they deteriorated to 3 MPa at 400 °C and increased up to 11 MPa at 800 °C. Even so, the geopolymers could withstand high temperature without any disintegration and spalling up to 800 °C. The formation of crystalline phases at higher temperature was observed deteriorating the strength of unfoamed geopolymers but enhance the strength of foamed geopolymers. In comparison, foamed geopolymer had better thermal resistance than unfoamed geopolymers as pores provide rooms to counteract the internal damage.